Human Flight

Factual Questions
1

A while back a friend posed this hypothetical question to my little circle of budds:

If you could pick one of three supernatural powers, which would it be: the ability to read minds, the power to turn invisible, or the power to fly? For reasons not relevant here, I picked the power to fly.

Today – as I endured an endless (earthbound) midtown Manhattan commute – I gave the matter some more thought and concluded that (at least compared to the other two kills) human flight should not be that difficult to crack. Not Rocky-the-Squirrel- or Superman-style flight, of course, but maybe some variation of Rocketeer-style flight.

(Yes, I know some company is working on a “flying car,” but I’m talking about more “flying” and less “car.”)

In the 60’s NASA (or some such military-industrial institution) invented those strap-on-your-back jet-packs that seemed to work pretty well. (At least they did in one or more episodes of Lost in Space and Gilligan’s Island, if I’m not mistaken.) And that was over thirty years ago! Something like that can’t possibly cost as much as an SUV, and if your object is to get to the Hamptons on a Friday afternoon, there’s just no contest.

So what’s the Uncrooked Dope? It’s the new millennium and we’re still letting all that space above our heads go to waste. Why aren’t we flying?!?

2

Main reason why jet packs never became very popular for production: You know all those times you see an out-of-gas car stuck alongside the road? THAT’s why.

Imagine this: You’re zipping along at a hundred miles an hour or so, enjoying your rocket pack, when you hear a slight sputtering. A few seconds later, you’re out of gas. Do you curse, pound on the stearing wheel, and pull over to the side of the road and begin pushing? Nope… you fall a thousand feet to your death.

Yeah, there was a decent jet pack built in the '60s. It was used in Thunderball and demonstrated at Disneyland. It worked the same way that a Harrier does: Push downward. The problem is that it’s fuel supply is dinky. You probably wouldn’t have gotten more than a mile or so on a full tank. Even with todays improved gas, I doubt you’d get more than a dozen miles out of one of those things.

Then there are safety issues… those things produce a significant amount of heat. And they’d probably be a bit more fragile than your average Ford, even the Pinto. So I guess you’re stuck with traffic, my friend. If you really want to get away from it, I suggest you move to Montana.

3

Let’s get the commute out of the equation right away - I’d go paranoid having to watch out for other commuters in three dimensions, it’s bad enough as it is. Commutes should be handled by public transportation, IMHO.

The rocket backpack has an endurance of less than two minutes flight time, not really what you want to use to hit the beach on a hot day.

I’ll admit up front that I’ve only dabbled in hang-gliding - we’ll need Johnny L.A. in here - but even this limited experience is an eyeopener in at least three respects:

  • Flying is way more complex than driving - it’s not only in 3 dimensions, but air has the disturbing habit of being invisible and in motion relative to the ground. It takes some practice before you’re able to estimate how the turn you’re about to make with your aircraft (you turn relative to the air, remember ?) will change its attitude and speed relative to the ground. Rather important when landing, very important when landing a glider (one try!). Getting it wrong hurts.

  • If a car breaks, you pull over. If an aircraft breaks, you fall down. Your safety margin needs to be much higher in an aircraft.

  • The weather means everything and can ground you anytime.

But for recreational flying: If you’re willing to plunk down the equivalent of a SUV, you’re almost there. Look into sailplanes or perhaps ultralights. Here in Germany, I could easily own a very nice ultralight plane if I’d give up my motorcycle (fat chance!).

And as to why so few people are actually flying: Search me.

4

Ya know…? I want a jet pack! I think the major problem with it is its range. SPOOFE is right. You wouldn’t get very far on the fuel it carries. And if you carry more fuel you need to have more power to lift it… which requires more fuel!

Now for “volantors”. Moller has developed the Skycar. (See http://www.moller.com/skycar/m400/ and http://www.freedom-motors.com/skycar.html for pics.) Interestingly, the M150 looks like it was built on a BD-5 fuselage. I read about these beasties in the 80s in Popular Mechanics or Mechanics Illustrated. The glowing articles talked about how much more efficient travelling would be with this “magic carpet”. Here’s part of a BBC article about it. http://news.bbc.co.uk/hi/english/sci/tech/newsid_354000/354129.stm

That sounds pretty good; but check out this earlier paragraph:

Yes, you will need a license. It is, after all, an aircraft! You’d need at least a Private certificate and a multi-engine rating. I’d been confused about what the “powered lift” aircraft was in the Federal Aviation Regulations. Moller’s site indicates that the Skycar would fall under this category.

What about practicality? I’ll admit that I have a very low opinion of the average motorist. While I’m not a test pilot, Tom Wolfe hit it on the head in his book The Right Stuff when he wrote that pilots consider themselves better at operating any vehicle than non-pilots. (It’s amazing our egos actually fit into the cockpits!) Computer-controlled or not, can you imagine having hundreds of thousands of these things zipping around the typical commuter routes? The carnage would be glorious!

Face it. People don’t maintain their cars very well. Now they’re going to have a “car” with eight engines? Sure, it will fly if one fails. So many people (or is that “manny people” ;)) will fly with one engine out. Or two. How many times have you, dear reader, delayed maintenance on your car?

Fuel efficiency. The BBC page says the Skycar gets about 8km/l. Hmmm. A little early for math, but if there are 4 litres in a gallon (approximately) and a km is 0.62 miles, then that’s about 20 miles per gallon. Better than the average mileage in my Jeep, but not spectacular.

Cost. Should be about $1 million for the first batch. Moller believes that if he can build 500,000 per year, the cost will fall to about $80,000.

Safety. Okay, this thing does have two ballistic parachutes to bring it down in an emergency. There are parachutes for the passengers. What about people on the ground? If Moller’s plans come to fruition, there will be hundreds of thousands of Skycars flying around our cities. Some of them will break. When they break they’ll come down. Airplane and helicopter pilots try to find a place to land, and nearly no one flies with a parachute. Although some aircraft do come down on top of buildings, most do not. What would happen if someone just decides to punch out any ol’ place?

I return to my opinion of drivers. People are not adequately trained to drive cars, and Moller wants to see them flying an aircraft? It’s easy the way he puts it. Just tell the computer what to do. You sit back and relax, and the computer does everything else. Are there any Windows users out there who would want to put their lives in the hands of a machine? The “Blue Screen of Death” would take on a whole new meaning!

I think the Skycar is a fascinating machine. I’d like to have one (if I could control it myself, not with a computer that does everything). But I don’t think it’s practical for the teaming millions. The Jetsons will have to wait.

5

I worked with a guy who lives in Big Bear and who works in Orange. He had a 1966 Piper Cherokee 140 that he would commute in. Much cheaper than a Skycar, although it would only do about 120 knots.

If you want to fly, you can get a used airplane for $20,000 - $50,000 easily. You can build your own Rotorway 2-place helicopter for about $60,000.

As to “powered-lift aircraft”, you still need to remember the old saying:

I’d say that’s a good thing to remember in a car, too.

6

I’m surprised tha no one noticed that Rocketeer style flight is just about impossible. Rockets don’t fly horizontally without wings for lift. They can fly with a vertical thrust vector or in a ballistic flight that’s sorta horizontal for a bit but there is no skimming along the cornfield or across the lake like in the Mercedes Benz ad without lift. There is such a thing as a lifting body but I don’t think a human body is sufficient for body surfing air.

7

Padeye,

Actually, there’s this cat who has a “bat suit”. Basically, it’s a skydiving jump-suit with bat-like webs between the arms and the body. The idea is to glide as far as possible before hitting the 'chute (you’re going way too fast for a soft touchdown). I think he may have gone 20 miles once.

I think that flying like the “Rocketeer” is theoretically possible, given the right suit and enough thrust; plus a parachute for landing. You can fly a barn door with enough thrust. But I don’t know of anyone fool enough to put it into practice.

8

I remeber seeing that guy with the bat suit, and he did glide for quite a distance, but he had to start at X-thousand feet to get that far without splatting on the earth.

9
      • I’d be pretty darn amazed if a powered-lift vehicle such as the Skycar can ever manage to get as much as 20 MPG. As I’ve read it, the main reason that the military has rejected powered-lift vehicles is that (aside from helicopters) they can’t get decent fuel economy/range out of them, price notwithstanding.
  • Helicopters aren’t real difficult to fly, and you can take off and land in a moderately sized back-yard. Yet 500,000 people don’t own helicopters, due to gov’t regulation and ensuing costs. I doubt any of us will live long enough to see a sky filled with Skycars. - MC
10

And sadly, the guy who came up with the idea ended up doing just that due to a faulty rig.

11

The Moller Skycar is another fantasy machine that will never become a reality. It’s been ‘two months away from flight test’ for about 15 years now. The numbers Moller posts for it are flatly impossible. Even if it worked it could never be certified. And even if it worked and could be certified, it’ll never be affordable. The thing uses four Wankel engines, tied to 8 fans. Then there’s the computerized fly-by-wire system, and all the actuators to drive it.

Porche tried to build just an aircraft engine a few years back. And even though it was fairly conventional, they lost money on the project, even selling them at something like $30K a pop. A standard propellor costs about $2000. A constant-speed prop starts at $5,000. The Skycar has eight of them. And four engines.

The airplane is technically possible to build. The basic mechanics would work. It’ll just never be safe, efficient, or cheap. My guess is that you’ll never see one fly, period.

Johnny: The reason the M200 skycar looks like it has a BD-5 fuselage is because it DOES have a BD-5 fuselage. Moller never mentions this - The thing you’re seeing is just a cool looking mockup. It’ll never fly, the fuselage isn’t structurally built to handle the pods on the sides, and it’s not aerodynamically optimum. It was just a cheap way for him to put together what looks like a cool little airplane. Those BD-5 fuselages are a dime a dozen, the remanants of thousands of unfinished kits purchased the last time a snake-oil salesman sold a plane with specs too good to be true.

12

dhanson,

Actually, the BD-5 was a wonderful little airplane. IIRC, the problems arose when they could not get the Hirth engines it was designed for back in the '70s.

My dad was building a BD-5A (short wings – 13 feet, I think) with the 90 h.p. option. But he never got the engine. A friend offered him a small turbojet engine for it, in exchange for 1/2 interest. Dad called Jim Bede who told him absolutely, positively, unequivocally and definately, that it was impossible to put a jet engine in a BD-5. A year later, Bede unveiled the BD-5J…

I think with the current crop of Rotax engines, the BD-5 is still viable. Indeed, I think there’s a company in Oregon that is marketing new kits (for about 5 times what Bede was charging). The only problem I’ve heard of with the design is that in certain stall configurations, the turbulent wash from the wings “blanks” out the stabilator making recovery impossible. I think it’s a power-off stall, IIRC.

As for dad’s BD-5A, it was 80% complete when the FAA moved him from Dagget to Lancaster, CA. The moving company dropped a ramp on it. crunch Dad’s workmanship was extraordinary. No one would ever see the lightening holes once the wing was assembled. He polished them. Based on the amount of work he put into it, the insurance company paid him $10,200, which was enough in 1976 to buy a 6-year-old Cessna 172.

13

What you really want isn’t some cumbersome 4-door sized flying ballistic missile to putter around in but your own personal VTOL helicopter pack. A now-defuct company called Solotrek was supposedly building one and had some neat pictures on their webpage, but it looked a bit unrealistic and now, 4 months after their debut, the webpage is “mysteriously” gone.

Here’s an short article that talks about rocket packs, flying platforms, and the Solotrek:

http://www.bayinsider.com/news/1999/09/10/fox2000_flying.html

Here’s some info about the Solotrek.

14

Y’know, when I think of Human Flight, I tend to think of the Gossamers. I carry too much avoirdupois with too little “wind” for them to ever work for me, but they still constitute my dream of Human Flight.

15

Your Dad is REALLY lucky that he never managed to finish his short-winged BD-5. As I recall, of the first 5 customer-built short-wings to be finished, four crashed on their first takeoff and the other one crashed on its first landing attempt.

The long wing BD-5 was better, and there are a few reasonably safe BD-5’s flying around now. But that’s due to the work of other engineers who came along and fixed Bede’s design flaws. I believe the really stable, flyable BD-5’s are the ones with the stretched fuselage and long wings.

Anyway, it’s a recipe for disaster to take a small airplane with tiny wheels and a high stall speed, and use it as the platform for an experimental engine/propellor combination. That’s one of the big problems with BD-5. Plus, it’s really hard to build them straight and within weight limits. And if you don’t manage both of those, you’ll be flying a very dangerous airplane.

Jim Bede is simply a poor engineer and a terrible businessman. He designed one good airplane, the BD-4. And he did the original design for the BD-1, which became the Grumman AA1 (I owned an AA1 for 6 years). I love that airplane, but its major faults are all Jim Bede signature stupid design decisions.

And let’s not forget the BD-10, which managed to kill a bunch of people before it was found that Bede screwed up the load calculations on the vertical tail surfaces, which would fail at normal cruise speeds.

16

A mere 3 or 4 days after my original post asking “Why aren’t we flying?” I see that tomorrow’s (6/11) NY Times Sunday Magazine has an entire article asking (and answering) same! (Title: “Canceled Flight” by Jaime Wolf; the article will surely be posted on the NYT website tomorrow; check it out soon though, 'cause after they archive it you gotta pay to read it.)

Wolf does a very comprehensive job of detailing the development of personal flying devices, and one can’t help but coming to the conclusion that – as I originally suspected – the technological problems are by no means insurmountable. I mean 60 mph for 30 mins. – which is the capability of the 1985 WASP II “flying garbage can” as Wolf calls it – is a vast improvement over the 20+ secs. flight time of the original Rocket Belt (a la James Bond and Lost in Space). The problem, it seems to me, is a lack of initiative and imagination on the part of the developers/manufacturers.

Regarding HorseloverFat’s earlier post about Solotrek: I had no trouble finding an up-and-running Solotrek website, so maybe they’re back in business. Frankly, I think (and hope) those guys are on to something.

A big “thank you” to all who posted replies to my question. But before I sign off to think of more of life’s great mysteries, here’s a parting observation that will, no doubt, get me into a lot of trouble and make me a lot of enemies:

I am pretty new to the Straight Dope online, though I’ve religiously read the hard-copy Q&As since the very first book was published. I love Cecil, I love the SD, and I even love most of my fellow posters.

Here’s my complaint: there are too many pooh-poohing, nay-saying, close-minded cynics who think they know why everything is wrong or can’t succeed … and boy do they want to let the world – and the SDMB – know it! I base this observation not just on the comments on this thread, but throughout the SDMB. (Take the thread about the new Sackie dollar coins, for example. All those posters, standing on their e-soap boxes proclaiming: THE SACKIES WILL NEVER SUCCEED! THE SACKIES WILL NEVER SUCCEED!) If you have an opinion, fine. But state it as such. It’s ironic that posters who would salivate at the opportunity to debunk fortune telling are the first to unflinchingly make such grand predictions.

Don’t get me wrong, I am a scientist at heart (though not by profession), and I am the first to denounce a crackpot idea when the evidence is in. But there’s too much opinion, speculation and theory out there that people are trumpeting as gospel.

A telling story with which to end my post. Then you may fire at will.

"There is an immortal entry in the Minutes of the Paris Academy of Sciences recording the reception of the first phonograph: “No sooner had the machine emitted a few words than the Permanent Secretary threw himself upon [the man conducting the demonstration], seizing his throat in a grip of iron. ‘You see, gentlemen,’ he exclaimed, ‘what it is…’ But, to the stupefication of everyone present, the machine continued to utter sounds.”

by Louis Pauwels & Jacques Berger
“The Morning After the Magicians”

(as excerpted in “Hodgepodge” by J. Bryan III)

17

It works for me now too, though I am also hoping they get them working and affordable it looks almost too good to be true.

18

Horse, I like your attitude! No nay-sayer you.

19

FYI, here’s the page address of that Times article:

http://www.nytimes.com/library/magazine/home/20000611mag-phenomenon.html

20

Go have a look at the ‘designer’ of the SoloTrek. His name is Moshier. Now go pick up just about any Popular Mechanics from 20 years ago until about 5 years ago, and you’ll see quarter-page and half-page ads for some amazing new flying plane from “Moshier Technologies”. It was always advertised with an ‘artist’s rendition’ drawing, or a picture of a mock-up on the ground. And if you wanted more, you could always order the special videotape or the ‘engineering manual’, or the cheaper ‘info-kit’. Needless to say, these were the real products. Why design an airplane when you can get an artist to draw one, then sell 20,000 info-kits at $20 a pop? When the demand wanes, quietly drop the ads, wait a few months or a year, then announce the next wonder-plane and watch the exact same suckers send you another $20. The Solo-Trek is probably the 10th Moshier ‘design’, and I don’t know of a single one of those airplanes that ever flew.

Here’s a hint when you’re evaluating a miraculous new design: Real airplane designers don’t take customer’s money until there is at least a prototype. Anyone who tries to take your money to sell you an ‘info-kit’ for an aircraft that exists only on paper is probably a con man, or so under-capitalized that he doesn’t have a snowball’s chance in hell of ever finishing his dream.

The SoloTrek has all the earmarks of a con job. I went to the web site, and never got past the first two screens before I was hit with suggestions that I go to the online store and buy a whole whack of official documents. The design itself has many, many problems (starting with the use of a 2-cycle engine, and the complete lack of any way to land safely if the engine fails (sorry, but a ballistic parachute is not a safe way to land. Ask any parachuter who has made an unlit night jump how safe it is to land in random terrain without the ability to steer), and many of the design ‘features’ look like gimmicks to appeal to the type of people who buy those info-kits. Things like a computer that FORCES you to land when fuel gets low (try certifying THAT one with the FAA), and that eyeball-retina gimmick to prevent unauthorized people from flying it (I guess these guys never heard of keys.)

Then we can go on and talk about the bogus claims made. For example, the one that says the single engine is really built like two engines, so it’s as safe as a twin (this claim is made because it has independent ignition systems. Never mind the fact that 99% of engine failure modes would cause the entire engine to quit, or that there is no redundancy in the rest of the drive train. Did I mention that 2-cycle engines only last about 500 hours between overhauls, and if they are not maintained really, really well tend to fail catastrophically at regular intervals?)

Look, I’m not a general naysayer. I’m a huge proponent of Aviation. I love experimental airplanes, and have helped build them. I’ve flown several experimentals including planes like the Glasair III (350 mph, yee-haw).

However, the aviation world is rife with scammers and con-men, because it attracts a lot of dreamers. And these guys do a lot of damage. Most of them never produce an airplane, and all they take are people’s money. Some of them do produce airplanes, and they kill people. These are high stakes, kids, so I speak out when I can. If you want to buy a homebuilt aircraft, there are lots of very safe, reputable designs out there. Buy one of them, and support the industry.

I honestly do wish the best for both Moller and Moshier. I’d love to see those aircraft fly. I’d be the first in line to buy one. But my experience tells me to be extremely skeptical.